I've been playing with Warsow recently, a free (as in beer) first person shooter based off of the Quake 3 engine.

It has some nifty graphics modifications like cel shading, but the best part is the emphasis on speed. It doesn't take long to start flying around levels at twice the normal running speed, with nifty tricks like bouncing off of walls and sliding up rails.

If anyone likes what they see, I may look in to setting up a server. =D

Warning: Bunny hopping and strafe jumping are required.

Sun Tzu said: "Now the general who wins a battle makes many calculations in his temple ere the battle is fought. The general who loses a battle makes but few calculations beforehand."